I think it depends on your Location,Certainly in the UK(going by Ebay ones I've seen)The Raven seems to have gone up in Value slightly.
The Raven only holds an air of mystery Value due to The minimal amount of units made/Bought and lack of people knowing about it per se and now Quasimidi No longer in existence,other than that its simply another Rompler thats only worth as much as someones willing to pay for it,try your luck on Ebay,you may strike it lucky or fall flat,again depends on location and abundance of Units in your Region certainly Europe you'd struggle to make your price
$850 seems a little high given its not in 100% cosmetic condition,When your looking at getting a good price for it flip the coin and look at its condition as a prospective buyer,Would you be prepared to buy it at that price like that with yellowing keys for that Value,I know I wouldn't.
I'd expect a mint condition with the maxx Board would be more in the region of 2/3rds of that value,mine only cost me £150 UK pounds and it was mint condition with the maxx Board fitted that was Four years ago....hence starting this Thread,but would still struggle to sell it for double that now!even with its pristine condition.
There's a Raven
On ebay,Starting price is a little High,I tend to think this puts people off Bidding...Still anything goes with ebay But I suspect this won't attract any bidders